VIENNA — Russian officials signaled that they could abandon diplomatic efforts to resolve the security crisis surrounding Ukraine, bringing a whirlwind week of European diplomacy to an ominous end and deflating hopes that negotiators could forge a path toward easing tensions in Eastern Europe.
One senior Russian diplomat said that talks with the West were approaching a “dead end,” while another said the Kremlin would wait until it receives written responses next week to its demands from Washington and from NATO before deciding how to proceed.
It was clear that Russia’s next move would be up to President Vladimir V. Putin, who, his spokesman said on Thursday, was being briefed regularly this week on negotiations with the West.
“The United States and its allies are actually saying ‘no’ to key elements of these texts,” Russia’s deputy foreign minister, Sergei A. Ryabkov, said, referring to the draft agreements with NATO and Washington that Russia published last month. “This is what we call a dead end or a different approach.”
The United States representative to Thursday’s meeting, Michael Carpenter, also depicted the two sides as engaged in a standoff with no clear resolution.
“We must never stand for the flouting or erosion of our bedrock principles,” Mr. Carpenter said. “That means no tolerance for overt or tacit spheres of influence, no restrictions on the sovereign right of nations to choose their own alliances, no privileging one state’s security requirements over those of another.”
Echoing the growing pessimism in Washington that the week’s discussions had de-escalated tensions, Mr. Carpenter told reporters that “the drumbeat of war is sounding loud and the rhetoric has gotten rather shrill.”
Russia is demanding that NATO drastically scale back its presence near Russia’s borders in Eastern Europe, including stopping all military cooperation with Ukraine and providing legally binding guarantees that the country will never join the alliance. Mr. Ryabkov said that dialogue with the United States was continuing but also warned that Mr. Putin was receiving options from the military about what to do “in the case of a deterioration of the situation.”
Those options, analysts and Western officials believe, are likely to involve new Russian military action against Ukraine. Joining this week’s discussions for the first time on Thursday, Ukraine said it had identified 106,000 Russian troops and 1,500 tanks near its border, and accused Moscow of pointing a “gun at our common European security.”
Thursday’s gathering, the last of three negotiating sessions this week between Russia and the West, took place in Vienna at a meeting of the 57-country Organization for Security and Cooperation in Europe, a group that includes Russia and Ukraine as well as the United States.
“It seems that the risk of war in the O.S.C.E. area is now greater than ever before in the last 30 years,” Foreign Minister Zbigniew Rau of Poland, which took over the rotating chairmanship of the organization this year, said in opening the session.
The West insists all countries must have the freedom to choose their alliances, while the Kremlin says that NATO cannot expand eastward, and that Western military cooperation with post-Soviet countries like Ukraine presents an existential threat to Russia’s security.
While Russian officials said this week that they were impressed with the seriousness with which the Biden administration — which the Kremlin sees as its main counterpart — engaged in the talks, there was no sign on Thursday that the impasse had been broken.
And while American officials say they are prepared to discuss some of Russia’s concerns — such as military exercises and missile placement in Eastern Europe — they reject discussion of Russia’s central demand to roll back NATO expansion.
In Moscow, Russia’s foreign minister, Sergey V. Lavrov, also adopted a pessimistic tone.
“The hard reality right now is that we were promised a written reaction,” Mr. Lavrov said in an interview aired on Thursday, according to the Interfax news agency. “We will wait for it. And then we will determine our next steps.”
Mr. Carpenter, asked about Mr. Lavrov’s comments, said he did not know whether or not such a written response was coming.
Ukraine, rejecting Russia’s denials that it had no plans to invade, said Russia’s massing of troops near the Ukrainian border needed to be reversed.
Understand the Escalating Tensions Over Ukraine
“The Russian leadership proves once again Moscow’s voluntarism to point the gun at our common European security at any moment they want,” said Ukraine’s representative, Yevhenii Tsymbaliuk.
Thursday’s talks were at a lower diplomatic level than the negotiations in Brussels and Geneva earlier this week, with no one above the ambassador rank in attendance from the key countries involved. Their host, the O.S.C.E., is expected to serve as a key venue for more negotiations if the Kremlin decides to pursue diplomacy.
“We are not indifferent to security objections voiced by participating states,” Mr. Rau, the Polish foreign minister, said. “I believe that the O.S.C.E. is the right platform to discuss every aspect of comprehensive security.”
It was the latest sign that Western countries are scrambling to engage with Russia, which has warned of a “military-technical” response if concerns over its security — such as overt Western military cooperation with Ukraine — are not addressed.
While Russia denies it has plans to invade Ukraine, researchers have identified some new signs of Russian troops moving toward the Ukrainian border in recent days.
Russia’s representative at the talks on Thursday in Vienna, Aleksandr Lukashevich, underscored that Moscow was not ruling out the possibility of further negotiations. Military analysts have noted that were Russia to invade Ukraine, the wintertime frozen ground would be advantageous to its heavy armor.
“If we do not hear a constructive response on our proposals in a reasonable time frame,” Mr. Lukashevich said in remarks released by his office, “we will be forced to draw the corresponding conclusions and take all necessary measures to assure the strategic balance and remove unacceptable threats to our national security.”
David E. Sanger contributed reporting from Washington, and Oleg Matsnev contributed from Moscow.